Achilles de khotinsky



' UNITED STATES- Q'FFICE.

" ATENT AOHILLES DE KHOTINZSKY, OF GELNHAUSEN, PRUSSIA, GERMANY.

SPECIFICATION forming part of Letters Patent No. 429,534, dated June 3, 1890.

Application filed February 3, 1890.

To all whom it may concern:

Be it known that I, ACHILLES DE KHOTIN- SKY, a subject of the Emperor of Russia, residing at Gelnhausen, Kingdom of Prussia, Germany, have invented new and useful Iniprovements in the Manufacture of Carbon Conductors for Electric Incandescent Lamps, whereof the following is a specification.

From the raw materials heretofore nearly exclusively employed in the production of carbon conductors for incandescent lamps it is difficult in an extensive manufacture to obtain a considerable number of conductors that are absolutely alike in transverse section and in quality. From this deficiency there results in the employment of the conductors in incandescent lamps an unequal luminous power and unequal consumption of current. The cause of this deficiency is that the raw material has a fibrous structure, which is still present in the conductors after their carbonization, as may be plainly observed under the microscope, and Wherefrom results a low degree of elasticity and inconsiderable and non-uniform density of the conductors.

The object of my invention consists in the manufacture of carbon conductors for incandescent lamps which do not possess the said disadvantages. For this purpose I use as raw material natural purified cellulose, preferably cotton which has been freed from fatty mat-- ter, and thereupon treated with muriatie or hydrofluoric acid, or both, in view of extracting mineral substances. Such cellulose I treat in well-dried state with sulphuric acid having a density of about Baum. The resulting gelatinous mass is washed first with water and thereupon with alcohol, so as to free the same from every trace of acid. The product thus obtained is colloid cellulose, which is absolutely homogeneous and amorphous, and which possesses the remarkable property of being soluble in distilled water. (This property is, however, inherent to the substance only if it is entirely void of acid.) From the said colloid cellulose carbon conduetors may be produced in two different manners.

First. The colloid cellulose is dissolved in distilled water, the solution is poured on plates of glass, and the water is allowed to Serial N0.339,081. (No model.)

evaporate. The plates of cellulose thus ob tained are cut or otherwise divided into strips. Previous to their being divided the plates may be passed between smooth rollers or pressed between even metal plates for the purpose of increasing their density and making their thickness more uniform.

Second. The colloid cellulose is dissolved in distilled Water, the solution is evaporated in oacuo with the aid of sulphuric acid to the consistency of sirup, and this mass is pressed through a'perforated plate having orifices of the desired form and size, the threads issuing from the said orifices being collected in a vessel containing ethyl alcohol, or any other suitable liquid which has the property of precipitating cellulose from its solutions in amorphous state. These strips or threads are carbonized as usual, and employed in the manufacture of incandescent lamps in known manner. I

By means of the described process an unlimited number of carbon conductors may be produced which are absolutely alike in their physical properties, in their transverse section, and in density. Besides this, the new conductors have greater density than other carbon conductors, as is proved by theirhigher specific gravity and inferior specific resistance. Finally, their elasticity is such that when having horseshoe form, or even when made with a loop, they may be bent straight without breaking, while on being thereafter released they rebound to their original state like a steel spring.

I am aware that heretofore conductors for electric lamps have been produced by converting fibrous cellulose by means of sulphuric acid into a gelatinous or fluid substance, forming sheets or strips therefrom,

and treating these with an alkali in view of neutralizing the acid. In this case the solvent contained in the said substance is sulphuric acid, and the acid is neutralized after the sheets or strips have been formed. In contradistinction to this method I produce gelatinous (colloid) cellulose which is soluble in water, a productheretofore entirely unknown, the said product being indeed also obtained by treating the fibrous cellulose in the first place with sulphuric acid, but only under the condition that the acid have a determinate degree of concentration of 50 Baum, or a little above or below, and in thereupon washing the colloid cellulose first with water, (which does not actas solvent so long as any acid remains in the substance,) and subsequently with alcohol, in View of removing, the last traces of acid. From this product I then make the sheets, plates, or threads by dissolving it in pure water and proceeding further as described. The acid is therefore according to my process completely removed from the colloid cellulose before it is formed into plates or threads.

I claim as my invention The process of manufacturing carbon con- ACIIILLES DE KHOTINSKY.

Witnesses:

J EAN GRUND, ALVESTO S. HOGUE. 

